Heater issues...

I've been having problems with the heater in my 2007 Pontiac Wave for a few years now. When the weather gets colder, the heater blows cool/luke-warm air and the dealership can't give me an explanation of why this is happening. It's frustrating because it doesn't happen all the time, but, it's starting to get more frequent this season. The engine temperature guage is in the normal postion all the time so I know the engine is warm, it just seems like something's stopping the heat from getting to the fan. I notice it the most when I stop at a light...the air is cool...this shouldn't be happening.

I guess I'm just wondering if any of you have had this problem. The dealership told me that it's probably not heating up completely because it's a small car with a small engine...it's only -2 degrees C outside...I don't buy it. I have full GM waranty so there is no reason why they should not fix this for me...they just keep telling me that they can't replicate the problem. My car's going into the dealership on Wednesday so hopefully they can do something about it this time.

Comments?

it could be clogged. But it could be the quite a few things, like the flap to the fresh air is stuck.

When does it occur? if it is no heat while moving and some heat while sitting still that could be attributed to bad thermostat. But when the weather is warmer (or the car is being worked on inside) the system would act normal.

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Originally Posted by petrified.rabbit

When does it occur?

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It's hit and miss, but, more frequent when the air gets cold around this time of year. It seems to act normal on the highway, but, in the city the air is cool, not just warm, cool, like you'd feel in the window was open a crack. When the car is being driven the air is slightly warm, and I mean slightly...and when I stop at a red light or something, the air is cool...no heat at all. The temperature is always just below half on the gauge, like it always has been.

I had a big problem with the anti-freeze resevior a few years back. There was a pinhole leak somewhere that was causing the anti-freeze to leak and they couldn't find it for months. One day I was on the highway when it was -40 degrees C and the hose connected to the resevoir blew right off....what a mess. Turned out there was a bad hose clamp from the factory and that's where the inital leak was. I don't know if this senario would cause damage to my heater core or thermostat or not.

If your car isn't even getting up to temperature it pretty much has to be the thermostat being stuck open.

The engine being small is a total BS line. My Aveo doesn't blow TONS of hot air like other cars I've had, but that needle always gets halfway up the gauge where it should be.

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Originally Posted by Chad

The dealership told me that it's probably not heating up completely because it's a small car with a small engine...it's only -2 degrees C outside...I don't buy it.

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You shouldn't - manual says hose going into the heater core should be AT LEAST 29C/84F when the engine has warmed up. Easy to check if you have a thermometer. Much lower than that, then you likely have a bad thermostat or blockage as others have already suggested.

Based on what you said about the temp gauge sitting in the proper range, I'd guess it is more likely a problem with the temperature door. Our Aveo is not around for me to check, but book says you should be able to hear the door hit the stops by turning off the ignition, moving the temp control to cold, then moving it rapidly to hot. Dealer needs to check this out if you can't hear it.

The variability of the temperature is weird. Had these symptoms on a different car that turned out to be caused by air accumulating in the system from a small leak in a connecting pipe near the top of the engine. So, wouldn't hurt to confirm your dealer has actually pressure tested your system if they're unable to find the cause.

Well, it looks like GM finally came through for me. After taking my car into the service department for the last 3 years with the same problem, they finally realized the cause was a bad thermostat. Now my heater blows hot air like it did when it was new, however, I still don't understand how they couldn't have found the problem the first time I took it to the dealership. I really like my car for the most part, but, for the amount of problems I've had in the past few years, my faith in GM's build quality and sevice knowledge is fading.

I remember taking a car (Dodge) to a dealership about five different times because of a stalling problem. They never diagnosed the problem which was a pretty basic thing in my opinion. The spark pickup was malfunctioning. Fortunately, I eventually solved the problem myself. I no longer use dealerships except to get parts that are not available anywhere else.

My car is still under warranty so it makes more sense to take it to them to get it fixed, but, it kinda makes you wonder what you're paying for if it takes that long to diagnose and repair minor problems like these. You're pretty much putting your faith in a code reader that tells the tech what to replace, and if the code reader can't tell them what to do, you're outta luck because they just clear the code, say they can't replicate the problem, and give you the car back.

thats it exactly, not very many mechanics are diagnosticians any more, instead they over charge you to hook up a scan tool it and then tell you to replace only that sensor, regardless if that is why the sensor is reading incorrectly.

( i fix a lot of cars that dealerships cannot)

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Originally Posted by Chad

... they finally realized the cause was a bad thermostat.

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Guess that means the Aveo temp gauge is no more informative than an idiot light... they could have saved a couple $/car.

the sensor for the gauge is positioned where the fluid gets hot. The open thermostat would keep the fluid fron retaining heat through the external parts of the system, like the heater core, bottle, etc..

if the gauge reads hot, your actually over heating the car, if it reads cold, the car isnt running or there is no fluid.

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Originally Posted by rodo

Guess that means the Aveo temp gauge is no more informative than an idiot light... they could have saved a couple $/car.

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The car likely was warmed up, just not fully up to temperature. Without something like a scangauge you'd never really be able to tell what your exact temperature is.

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Originally Posted by Daox

The car likely was warmed up, just not fully up to temperature. Without something like a scangauge you'd never really be able to tell what your exact temperature is.

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Yeah, even the old cars that had their gauges calibrated in degrees were not that accurate. However, there are still a number of cars and trucks with temp gauges that show relative changes very reliably - like when when a lower temp thermostat is installed or one fails open. You can tell on these cars whether or not it is reaching the target/"normal" operating temp. Though more are probably like the Aveo and keep the gauge for the "coolness" factor even when it doesn't tell the driver much more than what an idiot light could.

I was kidding about saving $/car, even though GM probably could. I still prefer the gauge because, unlike an idiot light, it's easier to notice when it has failed. How many people do you suppose actually check for missing idiot lights before they crank their engines? But then, I also appreciate the tachs that are left on automatics even when there are no sports shifting options. :)

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Originally Posted by petrified.rabbit

if the gauge reads hot, your actually over heating the car, if it reads cold, the car isnt running or there is no fluid.

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Don't know about reading cold if there is no fluid. Having witnessed a few catastrophic losses of coolant, there is still enough heat transferred from the gasses or adjacent metal to peg the gauge even when the fluid level has dropped way below the temp sensor.

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Originally Posted by rodo

Don't know about reading cold if there is no fluid. Having witnessed a few catastrophic losses of coolant, there is still enough heat transferred from the gasses or adjacent metal to peg the gauge even when the fluid level has dropped way below the temp sensor.

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I'll second that. I lost all the coolant from my resevoir on the highway last year. It was -45C that day and the guage was pegged at hot. Just another page in the story of my car.

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